Serum levels of protein HC and its IgA complex in malignant melanoma.

Protein HC is a low molecular weight glycoprotein that is present as free form and in complex with IgA (HC-IgA) in human body fluids. In the present report, a combined competitive and sandwich enzyme-linked immunsorbent assay (ELISA) was used to measure the levels of protein HC and its IgA complex independently in the sera of patients with malignant melanoma. The concentration of these proteins correlated with IgA levels and clinical staging. The main findings can be summarized as follows: (1) protein HC and protein HC-IgA complex levels presented the most significant elevation in melanoma stages IVA and IVB; (2) a significant positive correlation was found between protein HC and protein HC-IgA complex values and the clinical stage of the tumor; (3) protein HC-IgA complex and IgA concentrations are parameters with positive correlation both in normal controls and in patients with melanoma; (4) in normal sera, the levels of protein HC and protein HC-IgA complex are not correlated, however, they are negatively correlated in melanoma.